RFR: 8284161: Implementation of Virtual Threads (Preview) [v12]

[Joe Darcy]

On Thu, 5 May 2022 09:35:42 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> This is the implementation of JEP 425: Virtual Threads (Preview).
>> 
>> We will refresh this PR periodically to pick up changes and fixes from the loom repo.
>> 
>> Most of the new mechanisms in the HotSpot VM are disabled by default and require running with `--enable-preview` to enable.
>> 
>> The patch has support for x64 and aarch64 on the usual operating systems (Linux, macOS, and Windows). There are stubs (calling _Unimplemented_) for zero and some of the other ports. Additional ports can be contributed via PRs against the fibers branch in the loom repo.
>> 
>> There are changes in many areas. To reduce notifications/mails, the labels have been trimmed down for now to hotspot, serviceability and core-libs. We can add additional labels, if required, as the PR progresses.
>> 
>> The changes include a refresh of java.util.concurrent and ForkJoinPool from Doug Lea's CVS. These changes will probably be proposed and integrated in advance of this PR.
>> 
>> The changes include some non-exposed and low-level infrastructure to support the (in draft) JEPs for Structured Concurrency and Extent Locals. This is to make life a bit easier and avoid having to separate VM changes and juggle branches at this time.
>
> Alan Bateman has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 19 commits:
> 
>  - Refresh 12aa09ce7efd48425cc080d0b8761aca0f3e215f
>  - Merge with 1bb4de2e2868a539846ec48dd43fd623c2ba69a5
>  - Refresh d77f7a49af75bcc5b20686805ff82a93a20dde05
>  - Merge with 4b2c82200fdc01de868cf414e40a4d891e753f89
>  - Refresh 6091080db743ece5f1b2111fcc35a5f2179a403a
>  - Merge with cfcba1fccc8e3e6a68e1cb1826b70e076d5d83c4
>  - Refresh ee9fa8ed05ec22de7a13383052d68aa8aa7832ec
>  - Merge with jdk-19+20
>  - Refresh 7965cc6b168e567ac2596f2fbc3b00a7d99b7e1e
>  - Refresh 8d8f0a2fd646e57fe6b4e8ab669f836dc46dda69
>  - ... and 9 more: https://git.openjdk.java.net/jdk/compare/1bb4de2e...86bea8ec

Marked as reviewed by darcy (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/8166